Chiara Lansink1,2, Anouk Middelweerd1, Nienke Beerlage-de Jong3, Gozewijn Dirk Laverman1,2,1Department of Biomedical Signals and Systems, University of Twente, 7500 AE Enschede, The Netherlands, 2Department of Internal Medicine/Nephrology, Ziekenhuisgroep Twente, 7609 PP Almelo, The Netherlands, 3Section of Psychology, Health and Technology , Technical Medical Centre, University of Twente, 7522 NB Enschede, The Netherlands
Background: Diameter is an app-based lifestyle intervention for individuals with type 2 diabetes mellitus (T2DM). Based on established behavior change theories, the app delivers personalized coaching messages to facilitate behavior change related to physical activity and healthy eating. In addition, users can monitor glucose levels (FreeStyle Libre), physical activity (Fitbit), and dietary intake through an integrated food diary. This study examined the usage, acceptance, and user experiences of Diameter among people with T2DM.
Methods: Participants (adults with T2DM) were recruited in the hospital or primary care and used the Diameter for six months (10-week intervention, 12-week maintenance). Within these six months, there were three measurement points. Acceptance was assessed using mixed-method, the Unified Theory of Acceptance and Use of Technology 2 (UTAUT2) based questionnaire (7 point Likert scale) and semi structured interviews. Usage was derived from system log data (self-monitoring and coaching message engagement) and analyzed using descriptive statistics.
Results: A total of 74 participants were included, of whom 7 dropped out. Consequently, log data analyses included 67 participants (male = 36, age = 60.1), and questionnaire data 54 participants. Overall acceptance was rated high (M= 7.5 ± 1.3). System log data indicated low adherence to self-monitoring over time. Glucose monitoring was most frequently used, with only 16 participants (23.9%) recording valid data at all three measurement moments. Dietary self-monitoring showed the lowest adherence, with 3 participants (4.5%) completing all measurements. Physical activity data has not yet been analyzed.
Conclusion: The Diameter intervention was generally well accepted. Positive scores on hedonic motivation and effort expectancy suggest that the intervention was perceived as enjoyable and easy to use. However, sustained engagement with self-monitoring was limited.